I think they all say that. My provider Comcast doens't support Linux but it is
working great with SuSE 9.0.

I got to know that I have to get a router. Is that right? If yes -
Is it difficult to configure a router?

For a while I was using a Linksys router with Comcast and it worked with
no trouble. I used the MAC clone option so it had the same MAC as the Windows
PC that I originally used when I got connected with Comcast. Besides having to
set the MAC, I didn't have to do any other configuration of the router. Now
The SuSE 9.0 PC is now my router and that works with no trouble too. The only
thing I had to do with the SuSE PC is steal the net card from the Windows PC
because I have no idea how to clone a MAC in Linux

Does anybody have experience with installing broadband and Suse Linux?

Yes. I suspect there are others on this list with much more experience than
I have since I always had the simple connection type without ever having to deal
with such things as pppoe. A little off topic, what would be the equivalent
German expression for "piece of cake" (simple)?